This IB Maths AA SL Topic 4.12 – Standardisation and Inverse Normal resource develops students’ understanding of z-values and their role in normal distribution calculations. It begins by defining a z-value as the number of standard deviations a value lies above or below the mean. Students learn to standardise values using z = (x - μ)/σ and rearrange the formula as x = μ + zσ when converting a standardised value back to the original distribution.

The lesson then develops confidence in using normal cumulative distribution and inverse normal technology to calculate probabilities, percentiles, tail values, and central intervals. Students also apply inverse normal results to problems where the mean or standard deviation is unknown, including solving equations and simultaneous systems using given probabilities or percentiles. The resource includes real-world applications involving test scores, animal weights, battery lifetimes, and manufacturing data, alongside detailed TI-Nspire CX/CX II guidance. With clear explanations, worked examples, calculator instructions, interpretation tasks, and fully worked solutions, this resource helps SL students build strong standardisation and normal distribution skills in line with IB Mathematics AA expectations.